Sanding machine



June 23, 1936. 'r. L. HEDGPETH 2,044,982

SANDING MACHINE Filed March 6, 1955 2 Sheets-Sheet l .93 99 J flezvzz lffeofy vez June 23, 1936. 'r. L. HEDGPETH 2,044,982

' SANDING MACHINE Filed March 6, 1935 2 Sheets-Sheet 2 iiiii Patented June 23, 1936 SANDING MACHINE Theron L. Hedgpeth, Oak Park, Ill., asslgnor to Duro Metal Products Company, Chicago,

corporation of Illinois Application March 6, 1935, Serial No. 9,529

5 Claims.

The present invention relates to sanding machines, and is particularly concerned with portable abrasive devices adapted to be used for sanding or smoothing operations.

One of the objects of the invention is the provision of an improved portable sanding machine adapted to be driven by means of a flexible shaft and an electric motor or other suitable source of power. V

Another object of the invention is the provision of a portable sanding machine which is adapted to be driven by means of a motor and flexible shaft and adapted to be manipulated with greater i ease and better effect, due to simple structure.

Another object of the invention is the provision of a portable sanding machine of the type having an abrasive band which is adapted to beutilized in sanding operations in corners and other relatively inaccessible places so that practically all of a floor area or other similar area may be subjected to the sanding operation by means of the machine.

Another object of the invention is the provision of an improved sanding machine which is portable and which is provided with an abrasive of the belt type having an improved arrangement for tensioning the belt and also having an improved backing surface for supporting the active or working part of the belt.

Another object of the invention is the provision of an improved portable sanding machine which is simple in i construction, capable of economical manufacture and assembly, durable and adapted to be manufactured in large quantities at a very low cost so that it can be placed within the reach of a large number of users.

. Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the two sheets of drawings,

Fig. 1 is a view in perspective of a sanding machine constructed vention and including the driving motor and flexible shaft; 7

Fig. 2 is a side elevational view taken from the rear side of Fig. 1;

Fig. 3 is a sectional view taken on the plane of the line ii 53 of Fig. 2, looking in the direction of the arrows;

Fig. l is a sectional view taken on the plane oi the line ii of Fig. 2, looking in the direction o the arrows;

its lightness and according to the present in- Fig. 5 is a the line 5-45 the arrows;'

Fig. 6 is a sectional view,

taken onthe plane of the line at of Fig. 2,1ooking in the direction of the arrows;

Fig. '1 is a top plan view member with the taken on the plane of the abrasive backing supporting shank in section, of the line "xi-11 of Fig. 2; and

Fig. 8 is a fragmentary sectional view showing the mode of faste ning the heat insulating pad and the anti-friction metal covering for the the arrows.

Referring to Fig.

abrasive backing member, the line t-8 of Fig. 7, looking taken on the plane of in the direction of l, it indicates in its entirety an improved sanding machine constructed according to the present invention,

driven by means of course, any type which may be lengths of flexible l2. Of f electric motor may be used,

including even the portable type, provided the motor is suitably mounted flexible shaft may also as shown, and any be employed, the flexible terior housing it a ing elements of wires or links it. The sanding machine ill is ported and partially housed by means of ing is, which may or held for operation type of shaft including an exnd the flexible or hinged drivprei'erably supa housbe provided with a substantially flat top it, a substantially flat side II, but

open .at the bottom and preferably open at one side, as shown in Fig. 2.

. The width of the top it is preferably slightly less than that required to cover above the abrasive belt it so that the projects slightly beyond ing top it. At its ably provided with belt.

For example, the

be provided with a is of the belt preferably the edge 20 of the housfree end 2i the housing may preferedge an enlarged housing portion of .40 sufficient size to house both the belt pulley at that end and the adjusting means for tensioning the housing enlargement 22 may substantially flat top 23, a flat side it, a substantially fiat end 25, and a concave portion 26.

All of the metal parts of the device with the exception of the stock bolts and screws, shafts and bearings are aluminum alloy and of device may be constructed as and so that the complete assembly as is consistent w the various parts.

preferably constructed of an cast metal so that the cheaply as possible will be as light ith the strength required. for The enlarged housing portion of the handle are provided with suitable apertures for receiving the securing screw bolts 33 which pass through these apertures and are threaded into threaded bores in the housing I5.

Another knob-like handle 34, which may be constructed of wood or aluminum alloy, is preferably secured to the top l6 of the housing by means of a screw bolt 35 which is located in a bore 36 and counterbore 31 in the knob 34 and threaded home into a threaded bore 38 in the top |6... Knob 34 is adapted to be received in the ball-of the hand, the fingers passing under the knob for lifting and manipulating the sanding machine.

Referring to Fig. 2, the housing I5 is provided at the juncture between the enlarged portion 22 and the top i6 with a relatively thick upwardly extending flange 39. Flange 39 is provided with a pair of spaced transverse cylindrical bores 46 and 4| for passing a pair of guide bolts 42, 43 which carry a bearing bracket 44. The guide bolts 42, 43 are provided with nuts 45 at their outer ends for drawing the bearing bracket toward the flange 39, and the flange 39 is provided with a threaded bore 46 for receiving the threaded screw bolt 41, the end of which bears against the bearing bracket 44 and urges it in the opposite direction away from the flange 39. i

Bearing bracket 44 preferably comprises a cast metal member which is provided with a transversely extending arm 49 and a bearing supporting sleeve 58. The transversely extending arm 48 has two enlarged cylindrical lug portions 5| and 52 which are provided with cylindrical bores 53 for receiving the ends of the guide bolts 42, 43. Transverse threaded bores 54 are provided for receiving short set screws 55 which bear against the guide bolts 42, 43 and secure these uide bolts in the bearing bracket 44. The hearing bracket arm 48 is provided with an upwardly extending flange.56 joining the lugs 5|, 52, and providing a bearing surface for engagement with the end of the screw bolt 41;

The depending arm 49 is preferably formed of a pair of flanges 51, 58 at right angles to each other, thereby making the depending arm 49 of substantially T shape. The bearing supporting sleeve 50 extends'with its axis substantially parallel to the transverse arm 48 of the bearing bracket 44, and sleeve 59 has a cylindrical bore 59 within which are secured at each end thebearings 60, 6| of any suitable bearing metal. These bearings may be pressed in and secured by a close frictional flt, according to the usual bearing practice.

At its opposite end the housing l5 supports by means of the flat wall |1 an integral cast metal bearing sleeve 62 having a cylindrical bore 63 within which are secured bearings 64, 65 of any suitable bearing metal. The bearings 69, 6| are adapted to rotatably receive a ,drive shaft 66 which is provided with a knurled and tapered end 61 which is fixedly secured in the hub 69 of the I drive pulley 69.

Drive pulley 99 comprises a substantially cylindrical cast metal member which is preferably provided with a slight crown at the middle 19 so as to cause the belt to run toward the middle of the pulleys. The cylindrical body of the pulley 69 is joined to the hub 69 by a web 1| and a metal washer 12 is preferably placed upon the may be provided on the shaft by means of a i cylindrical collar 13 having a threaded bore 14 for a set screw 15 which secures the collar on the shaft 66.

The outer end of shaft 66 may be provided with a threaded bore 16 or with any suitable form of 1 connection for securement to the end 11 of the flexible shaft II. Of course, the thread in the bore 16 is such that the end 11 of the flexible shaft is driven home in the bore when the pulley 69 is driven. 1 The substantially cylindrical surface 19 of the pulley 69 is covered with a relatively thick resilient and flexible cylindrical rubber tube 18. The rubber tube 18 grips the metal cylindrical surface 18 of the pulley and provides an antislip covering for engagement with the metal of the pulley and the interior of the abrasive belt.

The other pulley 19 is substantially identical in construction and is fixedly secured to a shaft 89 located in the bearings 64, 65. Similar washers 8|, 82 may be employed, and shaft is provided with a similar thrust bearing 83.

The pulleys 69, 19 support an abrasive belt 84 which may consist of a strip of abrasive material such as emery cloth, sand paper or sand bearing fabric, or any flexible abrasive material. The ends of the strip of abrasive material are cemented together, preferably along a diagonal line, in such manner as to provide a continuous abrasive belt which will flt over the two pulleys 69, 19 and be adapted to be drawn tight in between the pulleys. The upper part of the belt 84 is located immediately below the top i6, but out of contact therewith, the top of the pulleys being substantially below the inside of the top i6 of the hous- 4 ing. The lower part of the belt 84 is located substantially below the lower edge of the housing side l1 so that the housing may not interfere with the action of the abrasive belt.

The housing I5 is preferably provided on the 4 inside of its wall l1 with a relatively thick lug 85 adapted to support a backing member for the abrasive. The lug 85 is provided with a verti cally extending bore 86 for receiving the shank- 81 of the backing member.- The cylindrical shank 5 81 may be secured in the bore 86 by a set screw 88 which is threaded into the bore 89. Backing member 98 is shown in planin Fig. '1, and preferably consists of a cast metal member having a substantially flat bottom 9| and an upwardly extending border flange 92.-

A number of transverse reinforcing flanges 93 maybe provided on the top, and the top is formed with an upwardly extending lug 94 having a cylindrical bore 95 within which is secured the 6 knurled end ,96 of the shank or stub shaft 81 by a drive fit. The backing member is preferably rectangular in plan and of a width substantially equal to the width of the belt, but preferably not extending beyond the belt, particularly at the open side of the casing. Its length is such that it substantially fllls the space between the pulleys 69, 19 inside the'belt 84, and it is adapted to engage the flat portion of the belt at the bottom of the sanding machine between the pulleys to 70 on the work and by the sliding of the back of 75 and to the metal backing member and coextensive in area with the bottom of the backi member.

The backing member 9 is also preferably provided with a friction reducing covering such as a sheet steel member 99 of similar shape to the backing member and provided, as shown in Fig. 8, with an upwardly extending attaching flange Hill.

The anti-friction apron 99 is preferably provided with a resilient outwardly extending rib Hll, joining attaching flange I00 to the body of the apron 99. The attaching flange "I0 is located at the leading end of the apron, that is, the end toward which the abrasive belt moves.

Thus the resilient portion illl is adapted to give slightly and permit the apron 99 to adjust itself to the surface of the pad 81, 98 when pressure is applied to the abrasive, and thence to the backing member 90. The backing member 90 is, of course, adjusted so that it will engage the back of the belt M, and it may be so adjusted that it will cause the belt 8! to project slightly over the area of the backing member 90. Thus the back ing member 90 shapes the belt 84 into a flat work engaging surface and provides a -firm surface for backing up the flexible abrasive belt when it is applied to the work. The belt should be arranged so that it is drawn taut by adjusting the bearing bracket M by means of screw bolt 4i and guide bolts M, M.

The operation of the sanding machine will be evident from the preceding description. The sanding machine may be grasped with the right hand on the handle 21 and the left hand on the lmob 3t and applied to the work somewhat like a plane or other portable tool. Due to the fact that the working belt comes to the very edge of the tool as depicted in Fig. 3 and there are no other projecting parts to interfere with the operation ofthe edge of the abrasive belt at this point, the sander may be placed flatly against the wall at the edge of a floor, and practically the whole surface of the door may be treated by means of the machine. Only a very small portion in the corners of the room need be made the subject of hand sanding. The present sanding device may be used to sand in the direction of the grain or in any other direction relative to the grain, and when used in the former method it is adapted to produce a more finished smootg job than any sanding devices employing a rotary disc.

So far as I am aware, this is the first portable sanding device driven by a motorand flexible shaft and having a sanding belt with a flat work engaging surface, and the present tool is adapted to perform its work more evenly than any of the devices of the prior art.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all ces within the scope of the appended claims.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent of the United States, is:

l. in a sanding machine, the combination of a I cast metal housing provided with a top wall and a side wall, the bottom and other side being'open,

padof handle means carried by said housing, said housing having an enlargement at one end with an upwardly extending oflset wall, said side wall carrying a transversely extending bearing lug provided with a bore, bearing means in said lug, a movable bearing support comprising a. metal member having a pair of bores extending longitudinally of said housing and carried by a lug extending upinto said enlargement adjacent said offset wall, a pair of rods secured in said bores,

said rods extending through bores in said offset wall and being slidably supported in said latter bores, and threaded means located between said rods and threaded into said oilset wall for engaging said upwardly extending lug for moving said bearing means to tension an abrasive belt, pulleys rotatably mounted on shafts in each of said bearing means, and an abrasive belt carried by said pulleys.

2. In asanding machine, the combination of a cast metal housing provided with a top wall and a side wall, the bottom and other side being open, handle means carried by said housing, said housing having an enlargement at one end with an upwardly extending offset wall, said side wall carrywith a bore, bearing means in said lug, a movable bearing support comprising a metal member having a pair of bores extending longitudinally of said housing and carried by a lug extending up into said enlargement adjacent said odset wall, a pair of rods secured in said bores, said rods extending through bores in said offset wall and being slidably supported in said latter bores, and threaded means located between said rods and threaded into said offset wall for engaging said upwardly extending lug for moving said bearing means to tension an abrasive. belt, pulleys rotatably mounted on shafts in each of said bearing means, and an abrasive belt carried by said pulleys, the top wall of said housing terminating short of the free side of said pulleys and abrasive belt, whereby the abrasive belt is adapted to project beyond the walls of the housing to be brought into engagement with the work when located in a corner.

3. In a sanding machine, the combination of a housing having a top wall anda side wall. said housing supporting bearings parallel to each other at each end of the housing, a shaft in each of said bearings, a pulley carried by each of said shafts, said pulleys each comprising a cast metal member secured to said shaft by means of anchoring formations, beyond the walls of said housing at the open side of said housing, an abrasive belt mounted on said pulleys and likewise extending beyond the walls of said housing, whereby the housing does not interfere with the use of the abrasive belt on work when located adjacent a wall or the like, said housing having a vertlcalwall supporting one of said bearings, an inwardly extending lug on said vertical wall located inside of said belt, said lug having a vertically extending bore, and a set screw in a transverse bore for projection into said vertically extending bore, a cast metal backing member having an upwardly extending rod secured therein, said rod extending into said bore for securement in any predetermined adjusted position by said set screw, said backing member being provided with a resilient covering on its lower side and an apron secured to said backing member at its leading end and comprising a polished metal member for slidably engaging the inner side of the abrasive belt, said backing member being adapted to force the belt into engagement with a work piece.

4. In a sanding machine, the combination of a housing comprising a top wall and a vertical side wall, a pair of bearings supported by and at the ends of the housing, said bearings having parallel horizontal axes, shafts mounted in said bearings, pulleys carried by said shafts, means for driving one of said pulleys, .an abrasive belt mounted on said'pulleys, a lug on the vertical wall of the housing projecting into the space be- --tween the upper and lower runs of the belt, a ver-.

tical borein said lug, a. metal backing'member horizontally disposed in the space between the upper and lower runs of the belt, a vertical rod carried by said backing member extending upwardly into said resilient covering, presenting a smooth lower surface to the upper surface 0! the'lower run of the belt, and serving yieldingly to urge the said lower run of the belt into engagement with a work piece.

5. In a sanding machine, the combination of a housing comprising a top wall and a vertical side wall. a pair of bearings supported by and atthe ends of the housing, said bearings having parallel horizontal axes, shafts mounted in said bearings, pulleys carried by said shafts, means for driving one of said pulleys, an abrasive belt mounted on 'said pulleys, 9. lug on the vertical 1 wall of the housing projecting into the space between the upper and lower runs of the belt, a vertical-bore in said lug, a metal backing member horizontally disposed in the space between the upper and lower runs of the belt, a vertical rod 1 carried by said backing member extending upwardly into the vertical bore of the aforesaid lug, a set screw whereby said rod may be secured at various positions in the lug bore, and an apron secured to said backing member at its leading 2 end, said apron underlying the backing member, presenting a smooth lower surface to the upper surface of the lower run of the belt, and serving yieldlngly to urge the said lower run into engagement with a work piece.

THERON L. HEDGPETH.

of the belt 

